Measurement of Surface Shape by Scanning Electron Microscope : Using Detection Method of Normal Direction

Abstract

Simple method to measure surface roughness by scanning electron microscope has been developed, which integrates the back scattered electron signal along the horizontal scanning. However, the method was hard to be applied to the surface, the slope of which has inclination to arbitrary direction. This paper is concerned with measuring the surface shape for such case. Small ball was closely placed by the objective in the observation chamber, which is to be a standard of the signal intensity of the image. The normal direction of the ball sphere can be obtained for the respective signal intensity. 4 detectors were used to identify the image of the ball. The signal intensities of the image of the objective were identified by looking for the equal intensities on the ball. The normal direction of the objective can be replaced by that of the ball where the signal intensities were identified. An algorithm to form the surface shape from the normal directions on the objective was also proposed. This was applied to measure the indentation of Vickers hardness test and good results were obtained.